We would not recommend you to lock the focus in the invalidated control.
Usually in such scenario you would have a view model with several properties and a command or two, a view that has controls bound to the view model and the view model would set the can execute of the commands to false if the data is incorrect. The view would display red marks around the incorrect input but would not lock the user in the wrong control. And the buttons triggering the command would usually go disabled. That's pretty much the recommended way to handle validation.
Locking the focus results in bad user experience as one can not click "Cancel", can not fill other fields and go back to correct the wrong input etc. I am sure that you would hardly find an MS Office application that behaves the way you describe and even if you do it sure stress the user a lot.
Note also that the focus feature is part of the framework. We can not do much about it. You can try to lock the focus to the selected control but anything you do in that direction would be hacky.
the Telerik team
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